#include <stdio.h>
int main()
{
	int arr[] = { 1,2,3,4,5,6,7,8,9 };

	int k = 7;

	int sz = sizeof(arr) / sizeof(arr[0]);

	int lift = 0;

	int right = sz - 1;

	while (lift <= right)
	{
		int mid = (lift + right) / 2;
		if (arr[mid] < k)
		{
			lift = mid + 1;
		}
		else if (arr[mid] > k)
		{
			right = mid - 1;
		}
		else
		{
			printf("%d\n", mid);
			break;
		}
	}


	return 0;
}